This invention relates to a method of reducing air pollution, and more particularly relates to the reduction of air pollution by treating air polluting waste industrial flue gases of the type containing sulfur dioxide prior to discharge of the flue gases into the atmosphere. The treatment is accomplished in a manner effective to substantially reduce or eliminate the content of sulfur dioxide in the flue gases and remove it in the form of a sulfuric acid by-product.
Waste industrial flue gases arise in a number of industrial operations, amongst which is that of burning fossil fuels and particularly coal in plants for the generation of electricity. Smelting operations, including the smelting of copper and a variety of other ores, also cause the creation of a variety of air-polluting waste industrial flue gases.
Common to all of these waste flue gases is the varying content of sulfur dioxide therein, sometimes only at relatively low levels such as only about 2 or 3 or 4% by weight but sometimes as high as 10% or even possibly 20% or more by weight, but usually at a relatively low level as compared to the great volume or quantity of the industrial flue gas. However, even at lower weight percentages, the total quantity of the sulfur dioxide generated in the conduct of these industrial operations can significantly alter the atmosphere so as to contribute to acid rain problems and substantial damage to the habitat or environment for various forms of life on Earth.
Pitted against the damage to the environment is the cost for reducing the sulfur dioxide content of these waste industrial flue gases when the volume of the gas is so great as compared to the sulfur dioxide in the gases.
The present invention is directed to a solution to this problem and a solution which can effectively substantially eliminate the sulfur dioxide in waste industrial flue gases in an economically feasible manner that provides a by-product which offsets some of the cost of doing so.